This invention relates generally to an information storage library and more specifically to a robotic picker for data cartridges having a positive gripper for holding the cartridges.
An information storage library for a data processing system typically includes at least a media storage system for computer information data cartridges, a drive mechanism for placing the data onto the cartridges and removing the data from the cartridges, a picker also called a gripper or engagement mechanism for inserting cartridges into the drives or the storage locations or for extracting the cartridges from the drives or storage locations, and a transport mechanism for moving the picker and the cartridge between the drives and the storage locations. Computer information storage libraries include a removable media which, for example, could be disk cartridges, either magnetic or optical, and magnetic tape cartridges. Media storage systems include, for example, carousels, cylindrical silos, and slotted magazines or racks. A wide variety of pickers are included in the storage library systems. For example, frictional grippers with multiple fingers may be used or the cartridges may be simply pushed or pulled. In general, for any robotic picker, it is desirable to reduce complexity, weight and number of parts. In particular, it is desirable to reduce the number of electrically active devices to eliminate potential sources for malfunction and to eliminate problems associated with moving electrical connections. Typically the present day picker includes a grip mechanism which holds the cartridges through friction.
An example of such a mechanism is shown in the IBM Technical Disclosure Bulletin of August 1993 at pages 265-268 and titled xe2x80x9cAutomated Cartridge Tape Library Grip Mechanismxe2x80x9d. The gripper in the mechanism of the Technical Disclosure Bulletin is opened by activating a solenoid. The gripper grasps cartridges by means of a stationary finger and a pivoting thumb. The thumb is forced closed by grip springs. The thumb is pivoted open by energizing the solenoid. The solenoid is activated to place the gripper mechanism adjacent to the cartridge and then the solenoid is deactivated to grip the cartridge through friction applied through the springs. The grip springs cause the thumb to pivot closed thereby causing the cartridge to be squeezed between the thumb and finger. The problem with a frictional gripping mechanism is that the cartridge could be dislodged from the picker by contact with another mechanism or by an overactive cartridge holding mechanism in the storage system or drive mechanism.
It is, therefore, an object of the present invention to provide a picker mechanism that includes a gripper for positively gripping the cartridge.
Another picker for data cartridges is described in U.S. Pat. No. 5,687,039 issued on Nov. 11, 1997 to Paul Coffin, et al and assigned to the Hewlett-Packard company. This patent provides a dual fixed finger picker for gripping the cartridges. The fingers are fixed with regard to the picker and the picker must move vertically down to first allow the fingers to pass under the cartridge before engagement and then the picker must move vertically upward to engage the fingers with the cartridge. The picker can then draw the cartridge in and move to the next cartridge location. The picker can disengage the fingers from the cartridge with the similar combination of motions. The picker of this patent does not have a positive finger to provide a positive grip on the cartridge and relies mainly upon gravity to hold the cartridge on the fingers as the cartridge is drawn from the storage location or the drive.
Another object of the present invention, therefore, is to provide a positive gripper mechanism on a robotic picker that positively holds the cartridge without involved motions of the picker with regard to the cartridge.
There is an ongoing need for improved grippers for the pickers for computer information cartridges that provides a positive grip to hold the cartridge during transport between the storage area and the drives.
In view of the foregoing, it is an object of the present invention to provide a picker assembly having an enhanced gripping mechanism for holding cartridges while transporting the cartridges between the storage area and the drive mechanism of a computer library system.
It is another object to provide a gripper mechanism that positively hooks into the cartridge.
It is a further object of the invention to provide a gripper that positively interacts with the end of the cartridge while including balancing fingers to prevent the cartridge from disengaging with the gripper mechanism.
It is a further object of the present invention to provide a gripper that does not solely depend upon a frictional grip to hold a cartridge for transport in the library system.
These and other objects are achieved in this invention by providing an automated storage library having a media storage system for a plurality of data cartridges, at least one drive mechanism, a transport mechanism for moving the cartridges between the drives and the storage areas, the transport mechanism including a positive picker or gripper mechanism that includes a hooking finger for interacting with an end of the cartridge through a positive retention finger to hook into a centrally located lip provided on the bottom of the cartridge and at least one opposing finger to contact the top of the cartridge to balance the mechanical forces between the positive retention finger and the opposing finger. A solenoid may be used to open the fingers for locating the gripper adjacent to the cartridge, as shown in one embodiment. When the solenoid is deactivated, springs place the positive retention finger positively hooking into the lip of the cartridge and further springs positively bring the opposing fingers to contact the top of the cartridge to firmly grip the cartridge.
In a second embodiment, the transport mechanism includes a casing that surrounds the cartridge during transporting. At least the positive retention bearing spring is loaded open when the gripper mechanism is positioned to accept or release the cartridge located and closed to hook into the centrally located lip as the gripper mechanism loads the cartridge into the casing.
The foregoing and other features and advantages of the invention will be apparent from the following more particular description of the preferred embodiment of the invention, as illustrated in the accompanying drawings.